Pump assembly

Abstract

A pump assembly. The pump assembly may comprise a motor portion for driving a fluid pumping portion via a piston. The motor portion may comprise: a spool and a spool housing assembly having a spool chamber. The spool may be disposed within the spool chamber. The spool may comprise an upper portion and a lower portion, wherein the diameter of the lower portion is larger than the diameter of the upper portion. The spool may also comprise: (1) two support groove portions for cradling two slide valves and (2) two spool bores, which are in fluid communication with the two slide valves. The piston of the pump assembly may comprise a valve stem having a valve stem bore and valve stem openings. The valve stem openings may be funnel-shaped or may inwardly slope into the valve stem bore to prevent or minimize cutting or shredding of a blown seal.

What is claimed is: 
     
       1. A pump assembly, comprising:
 a motor portion; 
 wherein said motor portion comprises: a spool and a spool housing assembly comprises a spool chamber; 
 wherein said spool is disposed in and reciprocally movable within said spool chamber and comprises an upper portion and a lower portion; 
 wherein said spool housing assembly comprises: a first seal and a second seal; 
 wherein, when said spool is disposed within said spool chamber of said spool housing assembly, said first seal and said second seal divide said spool chamber into a proximal chamber, a supply chamber, and a distal chamber, respectively, such that:
 (i) said first seal divides said spool chamber into said proximal chamber and said supply chamber; and 
 (ii) said second seal divides said spool chamber into said supply chamber and said distal chamber; and 
 
 wherein a diameter of a lower portion of said spool is approximately 3 to 8 percent larger than a diameter of an upper portion of said spool. 
 
     
     
       2. The pump assembly of  claim 1 , wherein said diameter of said lower portion of said spool is approximately 4 percent larger than said diameter of said upper portion of said spool. 
     
     
       3. The pump assembly of  claim 1 , wherein said spool comprises a first support groove portion adapted to cradle a first slide valve; and
 wherein a width of said first support groove portion is approximately the same as a width of said first slide valve, such that said first support groove portion substantially prevents said first slide valve from moving laterally within said first support groove portion. 
 
     
     
       4. The pump assembly of  claim 3 , wherein said spool comprises a first spool bore; and
 wherein said first spool bore traverses laterally through said first support groove portion, such that said first slide valve is in fluid communication with said first spool bore when said first support groove cradles said first slide valve. 
 
     
     
       5. The pump assembly of  claim 4 , wherein a length of said first support groove portion is longer than a length of said first slide valve, such that said first support groove portion allows said first slide valve to move longitudinally within said first support groove portion. 
     
     
       6. The pump assembly of  claim 5 , wherein said spool comprises a second support groove portion adapted to cradle a second slide valve; and
 wherein a width and a length of said second support groove portion is approximately the same as a width and a length of said second slide valve, such that said second support groove portion prevents said second slide valve from moving either laterally or longitudinally within said second support groove portion. 
 
     
     
       7. The pump assembly of  claim 6 , wherein said spool comprises a second spool bore; and
 wherein said second spool bore traverses laterally through said second support groove portion, such that said second slide valve is in fluid communication with said second spool bore when said second support groove cradles said second slide valve. 
 
     
     
       8. The pump assembly of  claim 7 , wherein said spool housing assembly further comprises a ported wear plate;
 wherein said first slide valve moves longitudinally against said ported wear plate; and 
 wherein said ported wear plate comprises one or more stop portions that prevent said first slide valve from being out of position relative to said ported wear plate. 
 
     
     
       9. The pump assembly of  claim 1 , wherein said spool comprises a center bore that is adapted to moveably receive a valve stem of a piston of said pump assembly, said center bore being in fluid communication with said distal chamber of said spool housing assembly;
 wherein said valve stem comprises a valve stem bore and one or more valve stem openings; 
 wherein said one or more valve stein openings are tapered such that a shape of said one or more valve stem openings inwardly slopes into said valve stem bore; and 
 wherein said center bore, said valve stem bore; and said one or more valve stem openings are in fluid communication with each other. 
 
     
     
       10. A pump assembly, comprising:
 a motor portion adapted to drive a fluid pumping portion via a piston; 
 wherein said motor portion comprises: a spool and a spool housing assembly comprises a spool chamber; 
 wherein said spool is disposed in and reciprocally movable within said spool chamber and comprises an upper portion and a lower portion; 
 wherein said spool housing assembly comprises: a first seal and a second seal; 
 wherein said first seal is located inside said spool chamber and disposed between said lower portion of said spool and said spool housing assembly; 
 wherein said second seal is located inside said spool chamber and disposed between said upper portion of said spool and said spool housing assembly; 
 wherein, when said spool is disposed within said spool chamber of said spool housing assembly, said first seal and said second seal divide said spool chamber into a proximal chamber, a supply chamber, and a distal chamber, respectively, such that:
 (i) said first seal divides said spool chamber into said proximal chamber and said supply chamber; and 
 (ii) said second seal divides said spool chamber into said supply chamber and said distal chamber; and 
 
 wherein a diameter of a lower portion of said spool is approximately 3 to 8 percent larger than a diameter of an upper portion of said spool. 
 
     
     
       11. The pump assembly of  claim 10 , wherein said diameter of said lower portion of said spool is approximately 4 percent larger than said diameter of said upper portion of said spool. 
     
     
       12. The pump assembly of  claim 10 ; wherein said spool comprises a first support groove portion adapted to cradle a first slide valve; and
 wherein a width of said first support groove portion is approximately the same as a width of said first slide valve, such that said first support groove portion substantially prevents said first slide valve from moving laterally within said first support groove portion. 
 
     
     
       13. The pump assembly of  claim 12 ; wherein said spool comprises a first spool bore; and
 wherein said first spool bore traverses laterally through said first support groove portion, such that said first slide valve is in fluid communication with said first spool bore when said first support groove cradles said first slide valve. 
 
     
     
       14. The pump assembly of  claim 13 , wherein a length of said first support groove portion is longer than a length of said first slide valve, such that said first support groove portion allows said first slide valve to move longitudinally within said first support groove portion. 
     
     
       15. The pump assembly of  claim 14 ; wherein said spool comprises a second support groove portion adapted to cradle a second slide valve; and
 wherein a width and a length of said second support groove portion is approximately the same as a width and a length of said second slide valve, such that said second support groove portion prevents said second slide valve from moving either laterally or longitudinally within said second support groove portion. 
 
     
     
       16. The pump assembly of  claim 15 , wherein said spool comprises a second spool bore; and
 wherein said second spool bore traverses laterally through said second support groove portion, such that said second slide valve is in fluid communication with said second spool bore when said second support groove cradles said second slide valve. 
 
     
     
       17. The pump assembly of  claim 10 , wherein said spool comprises a center bore that is adapted to moveably receive a valve stem of said piston, said center bore being in fluid communication with said distal chamber of said spool housing assembly;
 wherein said valve stem comprises a valve stem bore and one or more valve stem openings; 
 wherein said one or more valve stem openings are tapered, such that a shape of said one or more valve stem openings inwardly slopes into said valve stem bore; and 
 wherein said center bore, said valve stem bore, and said one or more valve stem openings are in fluid communication with each other. 
 
     
     
       18. The pump assembly of  claim 17 , wherein said spool comprises a spool seal located near a lower portion of said spool;
 wherein said spool seal is disposed between said valve stem of said piston and said lower portion of said spool; and 
 wherein said one or more valve stem openings of said valve stem are adapted to never contact and pass said spool seal when said valve stem reciprocally moves within said center bore of said spool. 
 
     
     
       19. The pump assembly of  claim 18 , wherein said spool housing assembly further comprises a ported wear plate and one or more stop portions;
 wherein said first slide valve moves longitudinally against said ported wear plate; and 
 wherein said one or more stop portions prevent said first slide valve from being out of position relative to said ported wear plate. 
 
     
     
       20. A pump assembly, comprising:
 a motor portion and a fluid pumping portion; 
 wherein said motor portion is adapted to drive said fluid pumping portion via a piston; 
 wherein said motor portion comprises: a spool and a spool housing assembly comprises a spool chamber; 
 wherein said spool is disposed in and reciprocally movable within said spool chamber and comprises an upper portion and a lower portion; 
 wherein said spool housing assembly comprises: a first seal and a second seal; 
 wherein said first seal is located inside said spool chamber and disposed between said lower portion of said spool and said spool housing assembly; 
 wherein said second seal is located inside said spool chamber and disposed between said upper portion of said spool and said spool housing assembly; 
 wherein, when said spool is disposed within said spool chamber of said spool housing assembly, said first seal and said second seal divide said spool chamber into a proximal chamber, a supply chamber, and a distal chamber, respectively, such that:
 (i) said first seal divides said spool chamber into said proximal chamber and said supply chamber; and 
 (ii) said second seal divides said spool chamber into said supply chamber and said distal chamber; and 
 
 wherein said diameter of said lower portion of said spool is approximately 4 percent larger than said diameter of said upper portion of said spool; 
 wherein said spool comprises a first support groove portion, a second support groove portion, a first spool bore, and a second spool bore; 
 wherein said first support groove portion is adapted to cradle a first slide valve; 
 wherein a width of said first support groove portion is approximately the same as a width of said first slide valve, such that said first support groove portion substantially prevents said first slide valve from moving laterally within said first support groove portion; 
 wherein a length of said first support groove portion is longer than a length of said first slide valve, such that said first support groove portion allows said first slide valve to move longitudinally within said first support groove portion; 
 wherein said first spool bore traverses laterally through said first support groove portion, such that said first slide valve is in fluid communication with said first spool bore when said first support groove cradles said first slide valve; 
 wherein said second support groove portion is adapted to cradle a second slide valve; 
 wherein a width and a length of said second support groove portion is approximately the same as a width and a length of said second slide valve, such that said second support groove portion prevents said second slide valve from moving either laterally or longitudinally within said second support groove portion; 
 wherein said second spool bore traverses laterally through said second support groove portion, such that said second slide valve is in fluid communication with said second spool bore when said second support groove cradles said second slide valve; 
 wherein said spool comprises a center bore and a spool seal; 
 wherein said center bore of said spool is adapted to moveably receive a valve stem of said piston, said center bore being in fluid communication with said distal chamber of said spool housing assembly; 
 wherein said valve stem comprises a valve stem bore and one or more valve stem openings; 
 wherein said one or more valve stem openings are tapered, such that a shape of said one or more valve stem openings inwardly slopes into said valve stem bore; 
 wherein said center bore, said valve stem bore, and said one or more valve stem openings are in fluid communication with each other; 
 wherein said spool seal is located near a lower portion of said spool; 
 wherein said spool seal is disposed between said valve stem of said piston and said lower portion of said spool; and 
 wherein said one or more valve stem openings of said valve stem are adapted to never contact and pass said spool seal when said valve stem reciprocally moves within said center bore of said spool. 
 
     
     
       21. A pump assembly, comprising:
 a motor portion; 
 wherein said motor portion comprises: a spool and a spool housing assembly; 
 wherein said spool housing assembly comprises: a first seal, a second seal, a spool chamber, a ported wear plate, and one or more stop portions; 
 wherein said spool is disposed in and reciprocally movable within said spool chamber and comprises an upper portion and a lower portion; 
 wherein, when said spool is disposed within said spool chamber of said spool housing assembly, said first seal and said second seal divide said spool chamber into a proximal chamber, a supply chamber, and a distal chamber, respectively, such that:
 (iii) said first seal divides said spool chamber into said proximal chamber and said supply chamber; and 
 (iv) said second seal divides said spool chamber into said supply chamber and said distal chamber; and 
 
 wherein said spool comprises a first support groove portion adapted to cradle a first slide valve; 
 wherein a width of said first support groove portion is approximately same as a width of said first slide valve, such that said first support groove portion substantially prevents said first slide valve from moving laterally within said first support groove portion; 
 wherein a length of said first support groove portion is longer than a length of said first slide valve, such that said first support groove portion allows said first slide valve to move longitudinally within said first support groove portion; 
 wherein said first slide valve moves longitudinally against said ported wear plate; and 
 wherein said one or more stop portions prevent said first slide valve from being out of position relative to said ported wear plate. 
 
     
     
       22. The pump assembly of  claim 21 , wherein said spool comprises a first spool bore; and
 wherein said first spool bore traverses laterally through said first support groove portion, such that said first slide valve is in fluid communication with said first spool bore when said first support groove cradles said first slide valve. 
 
     
     
       23. The pump assembly of  claim 22 , wherein said spool comprises a second support groove portion adapted to cradle a second slide valve; and
 wherein a width and a length of said second support groove portion is approximately the same as a width and a length of said second slide valve, such that said second support groove portion prevents said second slide valve from moving either laterally or longitudinally within said second support groove portion. 
 
     
     
       24. The pump assembly of  claim 23 , wherein said spool comprises a second spool bore; and
 wherein said second spool bore traverses laterally through said second support groove portion, such that said second slide valve is in fluid communication with said second spool bore when said second support groove cradles said second slide valve. 
 
     
     
       25. The pump assembly of  claim 21 , wherein a diameter of a lower portion of said spool is larger than a diameter of an upper portion of said spool. 
     
     
       26. The pump assembly of  claim 25 , wherein said diameter of said lower portion of said spool is between approximately 3 to 8 percent larger than said diameter of said upper portion of said spool. 
     
     
       27. The pump assembly of  claim 26 , wherein said diameter of said lower portion of said spool is approximately 4 percent larger than said diameter of said upper portion of said spool. 
     
     
       28. The pump assembly of  claim 21  wherein said one or more stop portions are part of said ported wear plate. 
     
     
       29. The pump assembly of  claim 21  wherein said one or more stop portions are stop pins that are connected to said ported wear plate.